You know Riot, not every female character needs to have
a) the same "moe" face oval
b) the same body shape
A little diversity goes a long way.
Not to knock on the artists, but superimposing hooves on top of existing "90-60-90 teenager" model doesn't count as something radically new.
EDIT: Re: Soraka The Starchild: if you bother to read the lore, that is an honorary title bestowed upon Soraka, ordinary person at the time, for her ability to channel the energy of stars. She de-evolved into the unicorn we know today because she cursed Warwick to become a werewolf (ie, used her powers for evil). Being a mature, studied woman, fits her backstory better :P
Also, this comparison, is actually not accurate. The current image of Soraka is closer to this.